Aditya Gupta
Last Activity: 5 Years ago
we know that sin4A= 2sin2Acos2A
also, sin2A= 2t/(1+t^2) and cos2A= (1 – t^2)/(1+t^2), where t= tanA.
so, sin4A= 4t(1 – t^2)/(1+t^2)^2
but t= (a+root(1 – a))/(a+root(1+a))
substitute this value to get the final ans :)
further note that all the given options are wrong which can be verified by putting A= ½ and then checking all the options by a calculator.
kindly approve:)